code: def test_format():
      env_var = _EnvironmentVariable("foo", str, "")
      assert f"{env_var} bar" == "foo bar"
      assert f"{env_var!r} bar" == "'foo' bar"
  
file_path: mlflow/tests/test_environment_variables.py
imports: import os
  import pytest
  from mlflow.environment_variables import _BooleanEnvironmentVariable, _EnvironmentVariable
label_desc: Use image node_id 7 for calling a global function with example usage: test_format() without return types